The invention relates to a radial bearing comprising a cylindrical bearing outer member and a shaft arranged therein, the member and the shaft being rotatable with respect to each other. One of the cooperating bearing surfaces of the member and the shaft are provided with a pattern of shallow lubricant-pumping grooves which, during relative rotation between the member and the shaft, build up a pressure in a lubricant present between the shaft and the member.
A radial bearing of the kind described above is described in the Netherlands Patent Application No. 7609817 laid open to public inspection, to which U.S. Pat. No. 4,141,603 corresponds. In this known bearing, the shaft or the outer member is provided with at least three patterns of shallow lubricant-pumping grooves located in successive axial zones, the two outer patterns having grooves which exert their pumping effect in the same direction and the intermediate pattern having grooves pumping in the opposite direction. The result of this is that upon rotation of the shaft in one direction a pressure is built up in the lubricant present at the area of one outer pattern of grooves and the inner pattern of grooves, while upon rotation in the opposite direction a pressure is built up in the lubricant present at the area of the other outer pattern of grooves and the inner pattern of grooves. Thus, the bearing operates both upon rotation in one direction and upon rotation in the other direction.
A disadvantage of this known bearing is that with the different directions of rotation disturbing tilting moments occur in such a bearing. This is due to the fact that in one direction of rotation journalling takes place in one axial zone and in the other direction of rotation journalling takes place in another axial zone. Especially with self-adjusting bearings and more particularly with relatively heavily loaded bearings, patterns of grooves of the kind mentioned herein before cannot be used.